1. Field of the Invention
The invention is in the field of electrical connectors, and in a more particular sense relates to those connectors attachable to the end of a flexible power cord and having a longitudinally divided housing of electrical insulation material adapted to grip the attached power cord, and having a strain relief means engaging the cord responsive to its assembly with the housing and with the terminals of the male or female contact elements of the device.
2. Description of the Prior Art
In recent years, it has become more and more important that devices of the character described be, in the first place, made as safe and fool-proof as possible. To this end, standards have been established within the industry, and requirements have been set forth for the industry by Underwriters Laboratories as well as by a variety of local, state, and federal agencies.
Apart from the importance of providing safe electrical connectors, the industry has moved toward the design of devices of this nature, such as to facilitate to the maximum extent possible the attachment of power cords to the devices. This has been important to the industry both from the standpoint of permitting the ordinary homeowner to connect power cords to attachment plug caps and female cord connectors, as well as from the standpoint of permitting assembly of the electrical connectors with power cords in industry, during the manufacture of electrical appliances of the type utilizing power cords.
From the standpoint of safety, it is now recognized that whether the device be an attachment plug or alternatively a mating, female connector, it should have a dead-front, a term used in the industry for electrical connector designs in which the contact elements are protectively mounted in an electrically insulative face or front member that is not removable, and which is disposed as a barrier in front of the terminals used for connecting the stripped ends of the conductors of the power cord to the contact elements of the device.
The provision of an electrical connector of the dead-front type obviously promotes safety, and thus aids in meeting the various standards established by Underwriters Laboratories and by the industry itself, as well as the standards established by various governmental agencies. However, it is recognized in the industry that ordinarily, the provision of a dead-front type of electrical connector involves a more expensive construction, by reason of the fact that normally, an excessive number of separate parts must be utilized in achieving the desirable result of a dead-front device of the character described. As a result, recent connector designs utilize the concept of housings integrally molded with movable portions, utilizing for example the concept of integral hinges or the like. This has led to the development of dead-front types of electrical connectors in which the housings are sometimes loosely but aptly described as being of the "valise" type, in the sense of utilizing opposed sidewall members integral with a dead-front, and adapted to be swung toward each other to a closed position from an initial, fully open arrangement. Such an arrangement is shown, for example, in patents such as U.S. Pat. No. 4,067,634 issued Jan. 10, 1978. Other devices, also formed with integral hinges, have been described, again aptly, as being of the "clam shell" type, a construction which again utilizes the concept of integrally joined, relatively swingable members movable between an open condition exposing the terminals for wiring purposes, and a closed position in which the terminals are concealed in back of a dead-front and the conductor is effectively clamped and strain-relieved between the housing portions.
In the prior art, the connectors heretofore designed, and described briefly above, have in many instances required extremely close tolerancing in respect to the molded portions of the housing, and have necessitated expensive molds, close inspection and quality control, and have had other deficiencies in respect to complete accessibility of the terminals for wiring purposes and effectiveness of the strain-relief means incorporated in the fully assembled device.